Pending U.S. patent application Ser. No. 12/618,256, filed on Nov. 13, 2009 and entitled “Anthropometrically Governed Occupant Support” describes an articulable support, such as a hospital bed, whose articulation depends at least in part on anthropometric considerations. The contents of application Ser. No. 12/618,256 are incorporated herein by reference. The application discloses a mode of operation in which rotation of a bed upper body section is accompanied by longitudinal translation of the upper body section and “parallel translation” of an upper body deck panel. The application defines parallel translation as translation of the deck panel in a direction parallel to the existing angular orientation of the upper body section.
The teachings of the earlier application are presented in the context of a bed having three actuators for controlling motions of the upper body section. One of these actuators controls the parallel translation. The other two are operated to rotate the upper body section while concurrently translating it longitudinally, to rotate the upper body section without imparting any longitudinal translation, or to translate the upper body section longitudinally without imparting any rotation. Although such a system may be desirable in a prototype or experimental bed to allow maximum flexibility of articulation during testing and development, it is envisioned that beds produced for commercial sale will include fewer actuators for the upper body section. Accordingly, the application also describes a bed with a simplified kinematic configuration having a single upper body section actuator and a dual rack and pinion. In operation the actuator extends or retracts to translate the upper body section longitudinally while changing its angular orientation. At the same time the dual rack and pinion effects the desired parallel translation of the upper body deck panel in response to the translation and orientation of the upper body section.
Notwithstanding the merits of the simplified kinematics and dual rack and pinion described in the earlier application, applicants continue to pursue additional innovations which may lead to improved performance, increased reliability and reduced cost.